[P-AE16] Exoplanets

[PAE16-P08] On the origin of metal-rich close-in gas giants: planetesimals vs pebbles

*Masahiro Ikoma^1,2, Kento Kikuchi¹, Tadahiro Kimura¹, Akifumi Nakayama¹, Sho Shibata¹ (1.Department of Earth and Planetary Science, The University of Tokyo, 2.Division of Science, National Astronomical Observatory of Japan)

Keywords:Exoplanets, Formation, Interior

According to observed mass-radius relationships for transiting exoplanets, many close-in gas giants contain large amounts of heavy elements (or metals). This fact may support the core accretion scenario for gas giant formation but brings a new challenge. Core accretion models suggest that such metals were likely injected into the gas giants after the core accretion stage. Here we explore the late accretion of metals for migrating gas giants based on two different scenarios: planetesimal accretion and pebble accretion. We show that metal-rich close-in gas giants like those detected so far can be formed under some conditions in both scenarios and, then, discuss the advantages and disadvantages of the two scenarios.